Abstract:
Carbon Dioxide (CO2) capture is one of the major industrial operation nowadays because of its harmfull effects on enviroment. CO2 is separated from flue gases to reduce the amount of greenhouse gasses in atmosphere, and removed from natural gas to provide clean energy with low footprint. Among the available techniques for CO2 separation, membrane technology has inherhet advantages such as low cost, high ernergy efficiency and potential for easier upscale. This research is conducted to combine cost and energy efficient membrane technology with highly selective Ionic Liquids (ILs) for the selective separation of CO2 from CH4 and N2. Two types of IL-based membranes i.e. three component mixed matrix membranes and supported ionic liquid membranes (SILMs), were fabricated. Zeolite imidazolate frameworks (ZIFs), a widely studied material, due to their structural resemblance to the inorganic zeolites and having characteristic properties of metal organic frameworks (MOFs) i.e. chemical, thermal and water stability, was used as third component of mixed matrix membranes (MMMs). Commercial IL, 1-butyl-3-methylimadzolium tetrafluoroborate, was used to modify ZIF-8 particles. The modified ZIF-8 particles were characterized by XRD, FTIR and SEM. These modified fillers were used in synthesis of three component MMMs. The performance of the membranes were tested for CO2 separation from CH4 and N2. Experiments were conducted at diffferent operating conditions to evaluate the commercial potential of membranes. In the second part of this thesis, supported ionic liquid membranes (SILMs) were prepared. A novel IL was synthesized based on Benziamdaole and Acetate ions. The incoporation of IL in membranes resulted in enhanced performance of membranes as MMMs showed a 193% increase in CO2 permeability and 47% increase in CO2/CH4 selectivity and SILM showed CO2 permeance of 19 GPU and CO2/CH4 selectivity of 37. These results clearly identify the potential of IL in membrane technology and potential application for effective and efficient CO2 separation. It is expected that the such membranes will play a vitol role as efficient separation materials, in particular for flue gas separation and natural gas purification.
